A time series causal model

Cause-effect relations are central in economic analysis. Uncovering empirical cause-effect relations is one of the main research activities of empirical economics. In this paper we develop a time series casual model to explore casual relations among economic time series. The time series causal model is grounded on the theory of inferred causation that is a probabilistic and graph-theoretic approach to causality featured with automated learning algorithms. Applying our model we are able to infer cause-effect relations that are implied by the observed time series data. The empirically inferred causal relations can then be used to test economic theoretical hypotheses, to provide evidence for formulation of theoretical hypotheses, and to carry out policy analysis. Time series causal models are closely related to the popular vector autoregressive (VAR) models in time series analysis. They can be viewed as restricted structural VAR models identified by the inferred causal relations.Inferred Causation, Automated Learning, VAR, Granger Causality, Wage-Price Spiral

Evaluation on crashworthiness and energy absorption of composite light airplane

[[abstract]]The main aim of this study was to explore the safety differences when using aluminum alloy and three different fiber reinforced composites as material for the cockpit and fuselage of light aircraft under crash landing. In accordance with the cockpit reduction amount stipulated by MIL-STD-1290A in which the reducing rates in all directions cannot exceed 15%, this study established the safety zones of impact speeds and impact angles. The overall safety zones of the carbon fiber reinforced composites and glass fiber reinforced composites cockpits were higher than that of the aluminum alloy cockpit by 38.56% and 32.12%, respectively. Among the four different fuselage materials, when carbon fiber reinforced composites was used as the cockpit material, except that the reducing rate for the crashing in the Y direction was slightly higher than the aluminum alloy cockpit, the reducing rate in the X direction and the inclined beam A direction during crashes were less than other materials, and the safety of its overall cockpit was also the most superior to other materials. The energy absorption capability of the aluminum alloy fuselage was better than the fuselages of all composite materials.[[notice]]補正完

Quotient triangulated categories

For a self-orthogonal module $T$, the relation between the quotient triangulated category $D^b(A)/K^b({\rm add} T)$ and the stable category of the Frobenius category of $T$-Cohen-Macaulay modules is investigated. In particular, for a Gorenstein algebra, we get a relative version of the description of the singularity category due to Happel. Also, the derived category of a Gorenstein algebra is explicitly given, inside the stable category of the graded module category of the corresponding trivial extension algebra, via Happel's functor $F: D^b(A) \longrightarrow T(A)^{\mathbb{Z}}{-}\underline{\rm mod}$.Comment: 14 pages. Manu. Math., to appea

the Transition Process in China: A theoretic and empirical Study

In this paper we analyse the driving forces of the transition from plan to market in China. A two segments and two sectors model is constructed to take into account the particular economic situation in China during the transition process: a large agricultural sector and an industrial sector; a large centrally planned segment and a market segment. The transition from plan to market is described by the increasing share the market segment in the whole economy on the one hand and the forced adjustment of the behaviour of the planned segment to the market situation on the other. Thus this model provides a well structured way to understand the complex phenomenon during the transition process and to analysis the driving forces of the transition process.Transition, Economic reform, Industrialization, Chinese economy

Subsampling Cointegration Ranks in Large Systems

In this paper we investigate the possibility of the application of subsampling procedure for testing cointegration relations in large multivariate systems. The subsampling technique is applied to overcome the difficulty of nonstandard distribution and nuisance parameters in testing for cointegration rank without an explicitly formulated structural model. The contribution in this paper is twofold: theoretically this paper shows that the subsampling testing procedure is consistent and has asymptotically power 1;practically this paper demonstrates that the subsampling procedure can be applied to determine the cointegration rank in large scale models, where the standard procedures hits already its limit. For empirical relevant cases our simulation studies show that centered subsampling improves decisively the performance of subsampling test procedure and makes it applicable also for cases when the number of independent stochastic trends are very large.Cointegration, Large Systems, Nonparametric Tests, Subsampling

Testing Cointegration Rank in Large Systems

In this paper we investigate the possibility of the application of subsampling procedure for testing cointegration relations in large multivariate systems. The subsampling technique is applied to overcome the difficulty of nonstandard distribution and nuisance parameters in testing for cointegration rank without an explicitly formulated structural model. The contribution in this paper is twofold: theoretically this paper shows that the subsampling testing procedure is consistent and asymptotically most powerful; practically this paper demonstrates that the subsampling procedure can be applied to determine the cointegration rank in large scale models, where the standard procedures hits already its limit. Especially for the cases of few stochastic trends in a system, the subsampling procedure shows robust and reliable results.Cointegration, Large System, Nonparametric Tests, Subsampling, PPP

What Happens to Japan if China Catches Cold? - A causal analysis of the Chinese growth and the Japanese growth

Many economic professionals like financial analysts, economic journalists and regulatory officers prevailingly regard the fast growth of the Chinese economy as the key factor that leads recently the Japanese economy to recover from the recession that started since beginning of the nineties. This judgement are mostly underpinned by statistical facts that the Chinese economy grew fast in the last two years; the Japanese export to China has experienced a dramatically increase during last two years, China has become now the biggest foreign trade partner of Japan and so on. However, this convincingly sounding arguments are not sufficient to conclude the statement that the Chinese growth leads Japan out of the recession. In fact the statement has essentially a causal character, which means both the interdependence and the directionality of the dependence. While the positive dependence/correlation between the Chinese economy and the Japanese economy is often explicitly documented by statistical facts, arguments about the directionality of the dependence are totally missing. In this paper we conduct an empirical study to investigate the directionality of the dependence in order to justify the statement empirically. Taking a probabilistic causal approach, we infer the causal dependence among the Japanese economy and the Chinese economy based on observed data. We find the evidence that the Chinese growth on average has been a positive cause of the Japanese since the later nineties and the temporary positive casual effect is even more pronounced.Inferred Causality, Recovery of the Japanese economy, China Japan relation